A wide range of research methods are used in psychology. These methods vary by the sources of information that are drawn on, how that information is sampled, and the types of instruments that are used in data collection. Methods also vary by whether they collect qualitative data, quantitative data or both.
Qualitative psychological research is where the research findings are not arrived at by statistical or other quantitative procedures. Quantitative psychological research is where the research findings result from mathematical modeling and statistical estimation or statistical inference. Since qualitative information can be handled as such statistically, the distinction relates to method, rather than the topic studied.
There are three main types of psychological research:
Correlational research
Descriptive research
Experimental research
The following are common research designs and data collection methods:
Archival research
Case study
Computer simulation (modeling)
Content analysis
Event sampling methodology, also referred to as experience sampling methodology (ESM), diary study, or ecological momentary assessment (EMA)
Experiment, often with separate treatment and control groups (see scientific control and design of experiments). See Experimental psychology for many details.
Field experiment
Interview, can be structured or unstructured.
Meta-analysis
Neuroimaging and other psychophysiological methods
Observational study, can be naturalistic (see natural experiment), participant or controlled.
Quasi-experiment
Self-report inventory
Survey, often with a random sample (see survey sampling)
Twin study
Research designs vary according to the period(s) of time over which data are collected:
Retrospective cohort study: Subjects are chosen, then data are collected on their past experiences.
Prospective cohort study: Subjects are recruited prior to the proposed independent effects being administered or occurring.
Cross-sectional study, in which a population are sampled on all proposed measures at one point in time.
Longitudinal study: Subjects are studied at multiple time points: May address the cohort effect and indicate causal directions of effects.
Research in psychology has been conducted with both animals and human subjects:
Animal study
Human subject research
